• Wind and Structures
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• v.10 no.3
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• pp.287-300
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• 2007

Wind action is a factor of fundamental importance in the structural design of light or slender constructions. Codes for structural design usually assume that the incident mean wind velocity is parallel to the ground, which constitutes a valid simplification for frequent winds caused by meteorological phenomena such as Extratropical Storms (EPS) or Tropical Storms. Wind effects due to other phenomena, such as thunderstorms, and its combination with EPS winds in so-called squall lines, are simply neglected. In this paper a model that describes the three-dimensional wind velocity field originated from a downburst in a thunderstorm (TS) is proposed. The model is based on a semi empirical representation of an axially-symmetrical flow line pattern that describes a stationary field, modulated by a function that accounts for the evolution of the wind velocity with time. The model allows the generation of a spatially and temporally variable velocity field, which also includes a fluctuating component of the velocity. All parameters employed in the model are related to meteorological variables, which are susceptible of statistical assessment. A background wind is also considered, in order to account for the translational velocity of the thunderstorm, normally due to local wind conditions. When the translation of the TS is caused by an EPS, a squall line is produced, causing the highest wind velocities associated with TS events. The resulting vertical velocity profiles were also studied and compared with existing models, such as the profiles proposed by Vicroy, et al. (1992) and Wood and Kwok (1998). The present model predicts horizontal velocity profiles that depend on the distance to the storm center, effect not considered by previous models, although the various proposals are globally compatible. The model can be applied in any region of interest, once the relevant meteorological variables are known, to simulate the excitation due to TS winds in the design of transmission lines, long-span crossings, cable-stayed bridges, towers or similar structures.

• Korean Journal of Community Nutrition
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• v.21 no.1
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• pp.12-24
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• 2016

Objectives: The objectives of the study were to investigate the school nutrition teachers' perception on their job and to find out recommendations needed for its improvement in order to provide a quality foodservice and nutrition education at schools. Methods: A total of 219 school nutrition teachers in Seoul were surveyed using selfadministered questionnaires. Results: The perceived importance of the 16 job duties was rated 3.8 based on a 5-point scale (1: very unimportant - 5: very important). The importance of six duties including nutrition management, production management, nutrition education, and food safety management were rated over 4 point but that of record-keeping for documents, official reporting, and service management was rated the lowest. Importance-Performance Analysis showed that nutrition management, receiving/storage management, production management, menu management, food safety management, and equipment/facilities management should be emphasized to maintain the current performance of duties. The performance of the nutrition education and counseling needed to be improved since the importance scores were greater than average but the performance scores were lower than the average. Official reporting and miscellaneous jobs were rated the highest for simplification need. More than half of the respondents agreed that equipment/facilities management, miscellaneous jobs, service staff supervision, and service line supervision could be allocated to other school departments. Conclusions: School nutrition teachers should invest more time and resources on their core job duties such as nutrition management, production management, food safety management, and nutrition education for providing quality foodservice and nutrition education. To reflect the environmental changes of school foodservice, a reasonable staffing index of school nutrition teachers needs to be developed. In addition, hiring an assistant or implementing school nutrition teacher internship programs can be useful to reduce workloads of the nutrition teachers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.12
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• pp.2747-2754
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• 2012

This thesis explains the development of multiple LCD system with the additional function to maximize the utilization of PC contents. The newly developed system is composed of host LCD and slave LCD. Host LCD decodes and outputs the image and voice of NTSC, PAL, SECAM signals. It also converts the decoded signals into LVDS signals before transmitting them to slave LCD stage. In addition, the installation of CF Memory and USB Memory helps display multi-media data. Unlike the host LCD, since not including the tuner and memory part, the slave LCD can't receive TV signals and play video signals. It only has the function to receive LVDS image signals and display on a LCD panel. This newly developed multi-LCD system has competitiveness in various aspects. With its simple structure, the failure rate, price and display power are relatively low due to its simplification of the control part. It has price and functional competitiveness as the product whose host LCD can control the entire slave LCD in terms of channel, volume, and video output.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.620-627
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• 2004

As h-bridge multilevel inverter is connected with series of single phase power cell, so it obtain high voltage using low voltage power semi-conductor and output voltage similar to sine wave. In this topology, the number of power cell increases in proportion to the output voltage level. Therefore, there are drawbacks that are responsibility against operating ability of main controller and signal wire increase. However, we can overcome this problems by the substitution of serial communication for the PWM signal in power cell control. Additionally, it has merits of reliability and maintenance. This paper deals with the synchronization and phase-shift method of power cell PWM using CAN(Controller Area Network) communication interrupt in H-bridge multilevel inverter. The advantages of proposed method are signal-line simplification using serial communication between main controller and cell controller, burden reduction in main controller, modularization of power cell, easy protection of each power cell, expandability improvement and reliability increase of control signal and power cell. This paper establishes propriety and reliability of proposed method through experiment of 13-level H-bridge multilevel inverter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.31-39
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• 2016

Power system engineers use power systems solution programs such as PSS/E, DSATool, Power World simulators for power system analysis. In this reason, KEPCO has begun to develop independent power system program, KW-PSS(KEPCO World Power system Solution) since 2002 and KW-PSS ver2.0 development was completed in 2011. However, it did not have much better functions compared with other programs. Therefore, we focused on the development of the practical and specialized functions. Consequently, PAZ(Power system AnalyZer) ver3.0 has been developed and it realized a differentiation than previous version. In other words, previous version focused on the basic function of power system analysis, PAZ ver3.0 has implemented many automated functions for power system operators were driven maximize operational efficiency. The unique feature of the implementation is as follows : Automated check for exceeding the breaker capacity, Scheduled outage automation, Control-file wizard for various voltage stability analysis, Scenario-based multiple transient stability analysis and Auto calculation of transmission line impedance. As shown in these functions, Those functions provide to use power system analysis easily by automation and simplification for power system engineers. We will secure national expertise through PAZ ver3.0. In addition it will be able to gain competitive edge through the steady development in the world market.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.1
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• pp.99-109
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• 2008

The purpose of this study was to survey sizing system and preferable ease and to decide the body measuring items for pattern making in a men's dress shirt for mass customization industry that is rising to the surface as a new production system. For this, it had a survey subjects were 254 males between 25 to 44 years old who wear dress shirt frequently and the relevant on line companies, and analyzed the garment sizing system and preferable ease. Collected data were analysed by frequency analysis, t-test, $X^2-test$, and ANOVA using SPSS 12.0 for window. Garment pattern making should reflect the sizes of the body parts well, and simplification of the ordering process would work as an important variable. In relation to the preferable ease, older people preferred more ease while younger people preferred fit ease. In relation to the sizes, people wearing the size of '110' preferred more ease than the size of '90'. And people weighing over 90kg preferred sufficient ease than less weighing. People height over 170cm people preferred sufficient ease for the length between shoulders than height under 170cm. In case of the companies had no consistent sizing system. Significant difference was found in the sizes, except for the size of '100', among those companies, there was significant difference in the length between shoulders and the length of the shirt among those companies and those sizes. Significant body parts for a garment pattern making was height, the circumference of the neck, the chest circumference, the length between biacromion, the arms length, and the waist circumference.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.327-332
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• 2006

In airborne gravimetry, there are two data streams. One is the specific force measured by an air/sea gravimeter or accelerometers, the other is kinematic acceleration measured by DGPS. And the difference of them provides the gravity disturbance information. To satisfy the requirement of most applications, an accuracy of 1mGal $(1mCal=10^{-5}m/s^{2})$ with a spatial resolution of 1km is the aim of current airborne gravimetry. There are two different methods to derive the kinematic acceleration. The generally used method is to differentiate the position twice, and the position can be calculated by commercial DGPS software. The main defect of this method is that integer ambiguities need to be fixed to get the precise position solution, but it's not a trivial thing for long base line. And to fix integer ambiguities, the noisier iono-free measurement is used. When differentiation is applied, noise is amplified and will influence the accuracy of acceleration. The other method is to get carrier phase acceleration by differentiate the carrier phase first, and then using the acceleration of GPS satellite to derive the vehicle acceleration. The main advantages include that fixing integer ambiguities is not needed anymore, position can be relaxed to about 10 meters, and smoother acceleration can be got since iono-free measurement is not needed. In some literatures, it's considered that the dynamic performance of the second method is inferior to that of the first. Through analysis, it is found that the performance degradation in dynamic environment results from the simplification of the GPS carrier phase observable model. And an iterative algorithm is presented to compensate the model error. Using a dynamic GPS data from an aeromagnetic survey, the importance of this compensation is showed at last.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.357-369
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• 2009

With the development and generalization of internet and information technology, airlines has tried to reduce their business expenses and commissions to travel agencies and enhance service qualities through service automation and simplification, such as internet booking and ticketing, self check-in, in-flight internet and RFID for checked baggage. The statistical techniques conducted for this empirical analysis are frequency analysis, reliability analysis, factor analysis, confirmatory factor analysis and multiple regression analysis. This research has tried to examine factors of airline e-services that influence on recommendation re-purchase intention and satisfaction. Results has found that only on-line reservation and ticketing factor had significant effect for recommendation and re-purchase intention and all e-service factors produced significant effect to total satisfaction. It was also recommend that airlines have to provide easy and more familiar e-service system to their passengers to deliver better services.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.33-42
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• 2018

This paper is based on the suggestions of the prior research on the buyer feedback, the selection of various product options, and the payment procedure improvements for Korea ON-line E-Procurement System(KONEPS), and this is to confirm the necessity of improvement and satisfaction from the viewpoint of the workers of the public and subordinate organizations the purchasing and using of the computer equipment in the actual KONEPS(Korea ON-line E-Procurement System). Based on the basic questionnaires and in-depth interviews, this paper conducts the qualitative case studies on IT and non - IT workers who had purchasing experiences for equipment at public institutions and government agencies in Gyeongbuk province. As results of the study, it was confirmed that the improvement is necessary for the buyer feedback and option selection part, and that there is a difference among the work experience for the simplification of the payment procedure and the satisfaction. In addition, the biggest contribution in the provided research is to categorize and to analyze the opinions on the use of public and relevant subordinate research participants. Additional work will be needed for a large number of workers in public and subordinate organizations who have purchasing experiences for handling various procurement products and those working in the metropolitan area and other public and subordinate agencies.

• Journal of Korean Home Economics Education Association
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• v.1 no.1
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• pp.53-62
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• 1989

Cooking practice is keenly related to not only the betterment of family health but to the improvement of dietary life. Cooking is a kind of practical skill and one is skill in it by repeated practice. The aim of cooking practice in school is to fix cooking method practically and scientifically, to acquire cooking skill. To achieve this aim there are many unrecognized or unsolved problems in the first-line schools. The problems and efficient ways of cooking practice in the middle and high school are as follows； 1. The aim of cooking practice： It should be first of all remembered that the practice is so practical that the knowledge and skill of cooking should be related to the future domestic life. Second, the practice should be able to serve the communal and national life by scientifying and improving life. 2. The content of the practice： First, it should be so arranged step by step that the content of each year should not be repeated. Second, the ratio of Korean cooking practice should be increased and the material of the practice should be chosen in consideration of the peculiarity of the community, seasons and economical problems so that it may be applied to the very day life. Third, to improve dietary life, the practice should be a way of the simplification of dietary life, of the nutritional efficiency. Forth, for the betterment of physical condition of the family the practice should involve balanced dietary plans and dietary therapy. 3. Teaching method： First, the practice should be scientific and comprehensive in consideration of not only cooking skills but also knowledge of nutrition. Second, micro-class system should be adopted, and practice labor should be allotted each student to develop cooperative attitude and the sense of responsibility. Third, in addition to the practice conducted in a body, comparative cooking, applicable cooking and experimental ability and the content of the text. Fourth, teachers should let the students examine and find problems by bringing them to a focus on the basis of theory. 4. Administration method： First, the practice schedule should be planned that a class has practices at least more than twice a semester. Second, two hours of class should be continued without cessation after beforehand survey and theory study. Third, facilities and utensils for practice should be enlarged. That is, cooking practice rooms, tools, utensils should be prepared. Fourth, enough cost of practice should be secured. The above mentioned points show the present situation and problems with which cooking practice teaching is confronted. In order to normalize cooking practice teaching, the first-line schools should give the above mentioned problems their careful consideration and improve the present situation so that efficient, creative, practical cooking practice will be possible.